An apparatus and method for preventing a driver from falling asleep by changing alarm sounding timing according to the state of the driver is conventionally known (see Japanese Patent Application Publication No. 2008-181327). When the eyes of a driver are closed for a period equal to or longer than a first threshold, Japanese Patent Application Publication No. 2008-181327 sounds the alarm for detection of a collision danger earlier than in a normal mode.
Japanese Patent Application Publication No. 2008-181327 is a technique pertaining to prevention of a driver's falling asleep, and is not configured to sound the alarm according to an action other than driving that the driver may perform during autonomous driving control in which a vehicle is driven autonomously.